Tree Flora of Jhalawar District (Rajasthan) - with Reference to Floristic Diversity and Phytogeography

Studies regarding the floristic diversity and phytogeographical affinities of Jhalawar district tree flora reveal that out of 182 upper storey cover species recorded in the area, 31 species were planted (cultivated) for various economic uses, while 151 species were found naturalized in the the area, 29 of the naturalized species, were also planted for edible fruits or as avenue trees or for timber in different parts of the district. 27 species were found growing near streams, rivers or in low lying areas, while 88 species were recorded in deciduous forests&hills tracts. On the contrary 37 upper storey cover species were observed in open, dry, gravelly and in other xeric conditions e.g. scrubby vegetations. 89 tree species were microphanerophytes, (Mi) 69 species demarcated as mesophanerophytes (Ms) and only 24 remaining species were reported to be megaphanerophytes (Mg) (large sized trees). Phenological studies about tree-flora indicated that flowering of 30 species initiated in rainy season, 70 species bloom in summer, 8 species flower round the year, while maximum, 74 species are laden with flowers in winter season, possibly due to photoperiodic temperature, humidity and light intensity requirements of these species. Possible reasons and plausible assumptions about the habit, habitat and physiognomy diversities have also been described. Exceptional presence of some species e.g. Adansonia digitata, (Tropical Africa), Prosopis cineraria (Arid zone species), Adina cordifolia and Mangifera indica (Subtropical forests), add new dimensions to the floristic diversity of the area as well as this may be due to the phytogeographical location of the locality which represents 1 : 1 ratio between eastern and western elements.